I have opened many rolls of Cents that were stuck like this. The old "Meghrig" brand tubes had a tendency to shrink and entomb the coins. My method is to use a hacksaw blade and cut the tube lengthwise, but not so deep to hit the edges of the coins. Leave a little plastic. Then put the blade of a flat blade screwdriver into the slot along the length and twist the screwdriver blade to break the remaining plastic, starting from the open end. Once you get to the bottom all the coins will come out, and there should be no damage or plastic residue on them. Works very well, though it does take some patience.
You're a glass half overfilled kind of guy, huh? Unfortunately, 68 was likely a big exaggeration and for good reason. Even in true OBW rolls, superb gems are far from the norm. Noisy/chattered uncs with a few decent eye-appealing examples is much more common. Have you considered a nice soak in acetone?
I would think slowly heating the plastic tube with a hair dryer would make it more pliable so you could then work the coins out of the tube. I would have thought putting it in the freezer would cause the plastic tube to shrink more than the coins. I don't like the idea of taking any saw to the tube.
I still have several cent rolls with this problem. I didn't have much luck with the freezer or a hair dryer. I had some luck by slapping the tubes flat on a hard surface. I gave up on the rest of the rolls and just put them away.
I would both freeze and use a hairdryer. The quarters may shrink a tad and the hairdryer would heat the plastic well before the metal. If that didn't work I'd start at the top and try peeling the plastic down the side. If you work slowly you can pull the top edge away from the coins and cut safely with an exacto knife. Slowly and carefully are the key words here.
Well, I tried several methods and none of the heating/cooling methods resulted in the coins coming out cleanly. Only the saw/snap open approach was sure-fire and has worked for me on perhaps 30 tubes. I have about that many more sitting in wait for me to set up and do the cuts. My future plan is not to use a hacksaw, but a table saw adjusted to cut just the right depth. However, I would NOT recommend this method since it requires some additional skill and equipment that many folks don't possess. Some point after I retire I plan to open the stack of Meghrigs and see what's in them!
Another vote for the freezer. Never tried it this way, but when cleaning estate pipes and the stem is stuck in the bowl, putting the pipe in the freezer for about 15 minutes loosens it enough to pull apart, rather easily. May take a little longer with the quarters, but definitely worth a shot.
My next best suggestion was going to be: toss them in a fire and collect the ingot after it dies down.
Liquid nitrogen using tongs incert the tube into a beaker half full of liquid nitrogen. Take out and drop tube on counter top bingo plastic in pieces coins freed.